Aviation emissions currently account for 2 to 2.5% of global CO2 emissions. Scenarios of future aviation project strong increases in air traffic and therefore emissions (UNEP Bridging the Emissions Gap).

The International Civil Aviation Organization (ICAO) has set a number of ‘goals’ for the environmental performance of international aviation: (1) a global annual average fuel efficiency improvement of 2 per cent until 2020 and an aspirational global fuel efficiency improvement rate of 2 per cent per annum from 2021 to 2050; (2) a medium term global aspirational goal of keeping the global net carbon emissions from international aviation from 2020 at the same level. Additionally, the US, Canada and Mexico have previously proposed a more ambitious, global goal to achieve a collective global goal of carbon neutral growth by 2020 based on a 2005 baseline, while Europe has proposed a 10% reduction by 2020 compared to 2005 levels.

In this work, the mitigation potential of i) technology and improved operations; ii) biofuels, and iii) the extension of current regional market-based measures to 2050 are quantified for low, central and high traffic growth projections.

Of the three types of measures studied, extension of current regional market-based measures (emissions trading) offers the greatest mitigation potential. None of the measures, or their combinations, for any growth scenario managed to meet ICAO’s aspirational 2020 carbon-neutral goal by 2050, the 2005 stabilization of emissions goal, or the 2005-10% stabilization of emissions goal. The 2% goal would only just be met by 2050, through assuming maximum reductions from technology, operations, and “speculative” availability of biofuels.

If a global emissions trading scheme were to be constructed that covered all international aviation, the emissions savings could be even larger than all other measures calculated in this study.

Click here to download hi-res figures from the main report (as a single zip file).

Click here to download hi-res figures from the appendix (as a single zip file).